A background blurred method has been widely applied in photography and video calls in recent years. Common background blurred techniques are described as follows. A shallow depth of field (DoF) photo shooting technique is typically adopted to emphasize the figure of a subject in an image when the photo is shot by an electronic device. In other words, the shallow DoF photo shooting technique is to focus a focal length of lenses on a specific range of distance in the image such that the figure of the subject within the range of distance can be sharpened and the background outside the range can be blurred.
Another way to generate blurred or sharp images is by modifying or adjusting photo shooting parameters of the camera. For example, a series of photos of a scene are shot using different focal lengths, and then the clearest position of each of the pixels in each of the images is respectively found. Afterwards, a relative DoF of each of the pixels in the image can be estimated according to a relationship between the focal length and the DoF. However, the technique requires an appropriate control of the photo shooting parameters by the user to estimate the relative DoF so as to obtain the image with a sharpened figure and a blurred background. For most users, modifying or adjusting photo shooting parameters is difficult.
Therefore, the electronic device capable of automatically blurring the background in the image can help the user to easily obtain the image with a sharpened figure and a blurred background.